It's likely connected to school shootings. A student making threats results in long-term suspension or expulsion as well as criminal charges for the protection

It's likely connected to school shootings. A student making threats results in long-term suspension or expulsion as well as criminal charges for the protection of other students (a suspended student who shows up at school can be arrested for trespassing without any other suspicious behavior). The lack of criminal charges in this case suggests the evidence isn't strong enough to support them, and it seems to me that similar standards should be applied to a long-term suspension or expulsion.